Backing two men on time (9)
I believe the answer is:
patronage
'backing' is the definition.
(synonyms)
'two men on time' is the wordplay.
'two men' can mean two substitutions for 'man'.
'man' becomes 'pat' ().
'man' becomes 'r' (abbreviation for rook, a chess piece or 'man').
'time' becomes 'age' (an age is a period of time).
'pat'+'r'+'on'+'age'='PATRONAGE'
(Other definitions for patronage that I've seen before include "custom in restaurant?" , "Condescension" , "Support" , "The power to control privileges" , "supporting role" .)